Dial Setting Research Articles

Molecular Dials: Hindered Rotations in Mono- and Diferrocenyl Anthracenes and Triptycenes

The syntheses, X-ray crystal structures, and molecular dynamics of 9-ferrocenylanthracene, 3, 9,10-diferrocenylanthracene, 4, 9-ferrocenyltriptycene, 7, and 9,10-diferrocenyltriptycene, 8, are reported. At 193 K, 3 exhibits C(s) symmetry via oscillation of the ferrocenyl only about the anthracene plane; at higher temperatures, complete rotation about the C(9)-ferrocenyl linkage becomes evident with a barrier of 10.6 kcal mol(-1). At 193 K, the ferrocenyls in 4 give rise to syn (C(2v)) and anti (C(2h)) rotamers that also interconvert at room temperature. In the corresponding triptycyl systems, 7 and 8, these rotational barriers increase to 17 kcal mol(-1); 9,10-diferrocenyltriptycene exists as slowly interconverting meso and racemic rotamers, in which the ferrocenyl moieties are, respectively, eclipsed (C(2v)) or staggered (C2). 2D-EXSY NMR data recorded with different mixing times indicate clearly that these interconversions proceed in a stepwise manner, for example, rac→meso→rac, thus behaving as a set of molecular dials.

Optimal Coordination of Directional Overcurrent Relays using Particle Swarm Optimization Technique

Abstract- The main function of the protective devices in the power system is to detect and remove the selected faulty parts as fast as possible. Directional over current relays are commonly used for the protection of interconnected sub transmission systems, distribution systems, or as a secondary protection of transmission systems. For the systems having more than one source connected, that is meshed or looped networks, directional over current relays become the suitable choice for better selectivity, since directional relays operate only when the fault current flows in the specific tripping direction desired. The most vital task when installing directional relays on the system is selecting their suitable current and time settings such that their fundamental protective functions are met under the requirements of sensitivity, selectivity, reliability and speed. The problem of setting Directional Over Current Relay(DOCR) is a highly constrained optimization problem that has been solved as a linear programming problem. The calculation of the time dial setting (TDS) and pick up current (IP) setting of the relays is the core of the coordination. This paper calculates the TDS by choosing one of the available pick up current settings as the predetermined value. The simplex two phase method is used to determine the optional TDS of the relays. Improvement in the solution is brought by using the particle swarm optimization technique to the co-ordination problem for reaching the global optimum value with less computational time. Sample 3 bus and 8 bus systems are utilized for comparing the results obtained by PSO with that of the simplex method. The optimization method used in the recent times minimizes the operating time of the relays much, when compared to the other methods. This method also enhances quicker solution of coordination process.

Calibration of the 1-MHz Sonitron Ultrasound System

Successful drug and gene delivery across cellular membranes can lead to improved therapeutic outcomes. Recent studies have suggested that sonoporation may enhance drug and gene delivery across cellular membranes. The enhancement may be a result of transient permeation of the membrane from cavitation or microstreaming effects of microbubbles exposed to ultrasound. Given limited acoustic pressure calibration and beam profile characterization of the Sonitron ultrasound systems in cellular bioeffects studies previously published, the objective of this work was to calibrate the acoustic output and explore the potential for standing waves in a cell-well plate. In this study, three 1-MHz transducers driven by Sonitron ultrasound systems, which have been used in a number of sonoporation studies, were calibrated. Transducers with 10-mm, 6-mm and 20-mm-diameter apertures (Sonitron 1000 and 2000, Rich-Mar, Inola, OK, USA) were calibrated using polyvinylidene fluoride (PVDF) needle hydrophones. Axial and transverse beam profiles were obtained, and the pressures were measured as a function of Sonitron intensity dial setting and duty cycle. The acoustic intensity was calculated and compared with the Sonitron intensity dial setting for duty cycles from 10–100%. Standing waves caused by reflections from the hydrophone holder were detected for each transducer. This observation may also have implications for in vitro sonoporation studies. Acoustic field characterization is an important first step in understanding the mechanisms of sonoporation and drug delivery across biomembranes. (E-mail: kopechja@uc.edu)

Effects of adding butorphanol to a balanced anaesthesia protocol during arthroscopic surgery in horses

Three groups of horses scheduled for arthroscopic surgery were premedicated with 0.025 mg/kg acepromazine, 88 μg/kg romifidine and 25 mg/kg guaifenesin, and anaesthesia was induced with 2.2 mg/kg ketamine. In...

Optimal coordination of over-current relays using modified differential evolution algorithms

Optimization of directional over-current relay (DOCR) settings is an important problem in electrical engineering. The optimization model of the problem turns out to be non-linear and highly constrained in which two settings namely time dial setting ( TDS) and plug setting ( PS) of each relay are considered as decision variables; the sum of the operating times of all the primary relays, which are expected to operate in order to clear the faults of their corresponding zones, is considered as an objective function. In the present study, three models are considered namely IEEE 3-bus model, IEEE 4-bus model and IEEE 6-bus model. To solve the problem, we have applied five newly developed versions of differential evolution (DE) called modified DE versions (MDE1, MDE2, MDE3, MDE4, and MDE5). The results are compared with the classical DE algorithm and with five more algorithms available in the literature; the numerical results show that the modified DE algorithms outperforms or perform at par with the other algorithms.

The Effect of Biomicroscope Illumination System on Grading Anterior Chamber Inflammation

To determine how a biomicroscope illumination system affects the grading of anterior chamber (AC) inflammation. Laboratory investigation. An artificial AC was designed to replicate optically a human AC and was filled with 5-mum polystyrene beads suspended in ethanol. A high-definition video eyepiece camera recorded the moving beads. Using image processing software, the main outcomes measures determined were the average number of beads in a 1 x 1-mm field at varying widths of the slit-beam. The volume of light and number of beads observed increased significantly as the slit-beam widened. Additionally, 3 separate biomicroscopes of identical make and model were found to produce different levels of luminance at the same aperture dial settings, influencing the number of beads observed, with the brighter biomicroscope yielding higher bead counts. Ability to count beads and perhaps the ability to count inflammatory cells in an inflamed eye depend on a number of factors, including the level of illumination and width of the slit-beam. This study demonstrated that the brighter the illumination and the wider the beam, the more beads were observed. This illustrates the importance of standardizing biomicroscopy, particularly where consecutive observations are used to make clinical decisions and in cases of multicenter clinical trials where clinical data are evaluated across different facilities.

Low-flow anaesthesia at a fixed flow rate

This study attempts to assess the safety of low-flow anaesthesia (LFA) at fixed flow rates with particular reference to the incidence of a decline in FiO(2) below safe levels of 0.3 and to determine whether LFA can be used safely in the absence of an FiO(2) monitor. A total of 100 patients undergoing procedures under general anaesthesia at fresh gas flows of 300 ml/min of O(2) and 300 ml/min of N(2)O were monitored while maintaining the dial setting of isoflurane at 1.5% for 2 h. The changes in gas composition were analysed and even a single recording of FiO(2) of <0.3 was considered sufficient to render the technique unsafe in the absence of gas monitors. The lowest recorded value of FiO(2) was 31% (v/v%). There was no incidence of adverse events necessitating the conversion from low flows to conventional flows. We conclude that low flows of 300 ml/min of N(2)O and 300 ml/min of oxygen can be used safely for a period of 2 h without the use of monitors for gas analysis of oxygen and agent in adult patients weighing between 40 and 75 kgs.

Desflurane-induced hemodynamic changes in patients with diabetic cardiovascular autonomic neuropathy.

Diabetic cardiovascular autonomic neuropathy (CAN) causes perioperative cardiovascular instability. A rapid increase in the desflurane concentration induces tachycardia and hypertension (HTN). This study examined the effects of the cardiovascular response to desflurane on patients with diabetic CAN. Forty diabetes mellitus (DM) patients with CAN were divided two groups: one with HTN (DM+HTN group, n = 17) and one without HTN (DM group, n = 23). The control group (n = 20) was composed of healthy patients without DM or HTN. In each group, the concentration of desflurane inspired was increased abruptly to 12.0 vol% 2 minutes after a thiopental injection. The target was to produce an end-tidal concentration of desflurane of 10.0 vol%, which was maintained until the end of the study by adjusting the vaporizer dial setting. The heart rate (HR), mean arterial pressure (MAP), and cardiac index (CI) were measured. The HR, MAP and CI increased significantly in all three groups when compared with the baseline (P<0.05). Additionally, the HR and MAP showed did not differ among the three groups at any of sampling times. However, the CI of the DM group and the DM+HTN group differed when compared with the control group at 90 and 120 seconds after intubation (P<0.05). In diabetic patients with CAN, the hemodynamic responses to a rapid increase in desflurane concentration are similar to those in non-diabetic patients before endotracheal intubation. However, after endotracheal intubation, increments in CI are blunted in diabetic patients with CAN.

The Diamedica Draw‐Over Vaporizer: a comparison of a new vaporizer with the Oxford Miniature Vaporizer

The Diamedica Draw-Over Vaporizer (DDV) has been developed as an alternative to the Oxford Miniature Vaporizer (OMV). Both can function as draw-over or plenum vaporizers. The performances of these two vaporizers were compared under conditions simulating intermittent positive pressure ventilation (IPPV) and continuous flow (CF). Series 1 experiments were conducted with the vaporizers in water baths at 20, 25 and 30 degrees C. Vaporizers were tested at dial settings of 1-4% over a range of minute volumes (1.75-6 l.min(-1)) and flow rates (3-8 l.min(-1)). Series 2 experiments compared output of the vaporizers over time at ambient temperatures of 20, 25 and 30 degrees C. A minute volume of 6 l.min(-1) (IPPV) and a gas flow of 8 l.min(-1) (CF) were used with a vaporizer setting of 2%. Vapour concentrations were recorded at 5-min intervals. In series 1 IPPV experiments, the DDV vaporizer was more accurate, producing significantly fewer vapour concentrations 0.5% more than or less than setting (p = 0.013). The OMV tended to produce more favourable results under continuous flow (p = 0.42). In series 2 experiments, the accuracy of both vaporizers was similar but consistency of output over time was better for the DDV and consistency of output according to differences in ambient temperature was better for the DDV. The OMV produced more vapour concentrations that were markedly higher than dial setting, particularly at high ambient temperatures. The DDV is a suitable alternative to the OMV with some distinct advantages. These include a larger reservoir, tendency towards greater accuracy during IPPV and improved consistency of output.

Evaluation of an Oxford Miniature Vaporizer Placed in-Circuit during the Maintenance Phase of Low-Flow Anaesthesia

The aim of the study was to assess Oxford Miniature Vaporizer output when mounted in-circuit during the maintenance phase of anaesthesia, using isoflurane, controlled ventilation and a fresh gas flow rate less than 1 l/min. Twenty patients of ASA Physical Status I and II were recruited from routine general surgical lists. All patients were paralysed and ventilated. An out-of-circuit isoflurane vaporiser was used during the induction period (first 20 to 30 minutes). Anaesthesia was maintained using an Oxford Miniature Vaporizer placed in-circuit, using a fresh gas flow of 500 ml/min. The end-tidal isoflurane concentration was recorded for 90 minutes at five-minute intervals using a sidestream agent analyser. Two groups were compared, with the Oxford Miniature Vaporizer dial setting at either the 0.5 mark (low output setting) or at the 1.0 mark (higher output setting). At a dial setting of 0.5, the Oxford Miniature Vaporizer produced a steady end-tidal isoflurane of 0.63% (95% confidence interval 0.60 to 0.66). However, when the dial was turned to 1.0 the output was almost always excessive and had to be reduced. These findings indicate that a stable, predictable and clinically useful output can be achieved when the Oxford Miniature Vaporizer is positioned in-circuit using low-flow and controlled ventilation.

Radionuclide calibrator measurements of 18F in a 3 ml plastic syringe

This paper discusses the calibration of Capintec radionuclide calibrators for the measurement of 18F in the pharmacy and clinic. In support of a planned regional comparison, a secondary laboratory was set up at Oak Ridge National Laboratories in Oak Ridge, TN. The laboratory was used to prepare 1 mL 18F-fluorodeoxyglucose sources in 3 mL plastic BD syringes (Becton, Dickinson and Company, Franklin Lakes, New Jersey, USA) and to determine dial settings in three models of radionuclide calibrators. Measurements were verified by comparing radionuclide calibrator measurements of a 5 mL ampoule source with previous results. The CIEMAT/NIST method of tritium efficiency tracing was used for activity determinations.

A new comprehensive genetic algorithm method for optimal overcurrent relays coordination

For optimal co-ordination of overcurrent relays, linear programming techniques such as simplex, two-phase simplex and dual simplex are used. Another way of optimal coordination program is using artificial intelligent system such as genetic algorithm (GA). In this paper, a powerful optimal coordination method based on GA is introduced. The objective function (OF) is developed to solve the problems of miscoordination and continuous or discrete time setting multiplier (TSM) or time dial setting (TDS). In other words; the novelty of the paper is the modification of the existing objective function of GA, by introducing a new parameter and adding a new term to OF, to handle miscoordination problems both for continues and discrete TSM or TDS. The method is applied to two different power system networks and from the obtained results it is revealed that the new method is efficient, accurate and flexible.

Phantom Anaesthetic Agent Trace?

With the increase in the management of patients with complex diseases and procedures, it may not always be possible to have a monitoring of anaesthetic agent trace due to restriction in the number of displayed waveforms. We report here an unusual incident of discrepancy in the numerical and waveform analysis of the anaesthetic agent, thus producing a potential source of patient injury. During a routine anaesthetic procedure with O 2 , N 2 O and isoflurane, we noted that the dial setting of upto 0.6% of isoflurane (Tec 7 vaporizer), mounted on an Ohmeda Aestiva/5 machine (Ohmeda, Helsinki, Finland) recorded no numerical anaesthetic concentration on the monitor. However, increasing the dial settings beyond 0.6% recorded the end tidal concentration, but with a lag of 0.6%. Preoperative check up of the machine was carried out in accordance with AAGBI guidelines [1]. A thorough check ruled out any leak, but we could smell isoflurane being delivered to the patient. Then, we switched over to the anaesthetic gas trace monitoring, and to our surprise we could get a trace even with dial settings as low as 0.2% (Figure 1). An increased concentration of isoflurane was being delivered to the patient. Then the vaporizer was changed to halothane, when the problem persisted. The quandary was not rectified even after calibration.

Effect of gloss and diffuse reflectance of display frames on visual comfort

Abstract— A series of 12 display frames of different combinations of gloss levels and diffuse reflectance levels was mounted on a display to test the visual comfort of 31 test subjects. The frames were tested in a controlled environment where a light reflex was purposefully visible on the frame. The intensity of the light reflex was controllable by the user, and the dial setting was recorded for each frame. The frames were also shown in two different test office environments, one light and one dark. Qualitative comments about the frames were recorded. A gloss level of 30 gloss units corresponded to about 30% of test subjects that wanted no reflex at all to be visible on the frame. There was a significant effect of frame gloss on the acceptable light level of the reflex. When the acceptable‐light‐level dial setting was converted to luminance contrast, the acceptable luminance contrast on the frames decreased with increasing gloss, and this effect was more pronounced for black frames.

Desflurane-induced Hemodynamic Changes in Patients with Hypertension

Background: A rapid increase in the desflurane concentration induces tachycardia and hypertension and increases the plasma catecholamine concentration. This study compared the desflurane-induced hemodynamic responses in hypertensive patients with those of normotensive patients. Methods: Sixty patients, 30 normotensive patient (group 1) and 30 hypertensive patients (group 2), were scheduled to undergo elective surgery under general anesthesia. The hypertensive patients have been taking regular antihypertensive drugs and their blood pressure and heart rate was well controlled. Thirty normotensive patients were not premedicated. The inspired concentration of desflurane through the mask was increased abruptly to 12.0 vol%. The target was to produce an end-tidal concentration of desflurane (ETdesf) of 10.0 vol% which was maintained until the end of the study by adjusting the vaporizer dial setting. The heart rate (HR), blood pressure (BP), cardiac index (CI), systemic vascular resistance (SVR), ETdesf, end-tidal concentration of carbon dioxide, and peripheral oxygen saturation were measured at the baseline and every 30 seconds for 5 minutes after inhaling of desflurane and for 2 minutes after intubation. Results: The HR, BP, and CI increased significantly in the two groups compared with the baseline. However, the HR, blood pressure, CI, SVR, and ETdesf were similar in both groups. In addition, there were no significant differences of hemodynamic changes between the β-blocker and the calcium channel blocker in the hypertensive patients. Conclusions: In patients with well-controlled hypertension, the hemodynamic responses to desflurane are similar to those in normotensive patients.

Evaluation of isoflurane and sevoflurane vaporizers over a wide range of oxygen flow rates

To examine the accuracy and precision of isoflurane and sevoflurane anesthetic vaporizers. 5 identical isoflurane and 5 identical sevoflurane vaporizers. Oxygen flow rates from 0.02 to 10 L/min were used with different vaporizer dial settings. Agent concentrations were measured at the common gas outlet by use of a refractometer. Accuracy was defined as the difference between measured agent concentrations, and dial settings were expressed as a percentage of the applied dial settings. Precision was defined as SD of the measured agent concentrations for each combination of dial setting and flow. Isoflurane values were generally greater than the dial settings. Accuracy of the isoflurane vaporizer was > 20% when 0.6% and 1% was dialed. Accuracy of the sevoflurane vaporizer was always within +/- 20% but decreased at 0.02 L/min flow and at combinations of high flow and high dial settings. Overall precision of the isoflurane vaporizer was better than that of the sevoflurane vaporizer. A possible explanation for the inaccuracy of the isoflurane vaporizer may be that it was manufactured to be accurate with air but not oxygen, which must be accounted for when using the vaporizer with oxygen, especially with nonrebreathing systems. The sevoflurane vaporizer may not deliver accurate agent concentrations at high flow and high dial settings. Both vaporizers are suitable for clinical use with a wide range of oxygen flow rates if these precautions are properly addressed.

An Unusual Cause of Faulty Tec 7 Vaporizer

To the Editor: We wish to report a problem with a vaporizer we encountered while anesthetizing a child. Routine check-up of all the equipment was done in accordance with association guidelines and no leaks were detected (1). A 2-yr-old child received inhalational induction with O2, N2O, and halothane, using Ohmeda Aestiva/5 machine (Ohmeda, Helsinki, Finland) with a Tec 7 vaporizer (in use for 7 mo) with 0.2%. Halothane was increased progressively by 0.5% every 3 to 4 breaths. With dial concentration of 5% for 3 to 4 min, the child was still not anesthetized and continued to struggle. The gas analyzer showed less inhaled concentration of the halothane than did the dial settings. The circuit was checked for any accidental disconnections. The gas analyzer was also checked for accidental misconnections or kinking. Visual inspection of the vaporizer filled with halothane revealed no obvious problem (Fig. 1), although the level of the halothane indicator had dropped. It was then decided to change the halothane vaporizer. Successful induction was thereby achieved.Figure 1.: Filled Tec 7 halothane vaporizer.To our surprise, examination of the vaporizer after draining the halothane revealed multiple cracks in the filling chamber beneath the crystal screen (Fig. 2). Backpressure of the vaporizer was checked and found to be normal, and it had never suffered any mechanical trauma. The vaporizer was returned to Ohmeda fortechnical assessment, but the engineers failed to explain the cause. The company was notified by mail to no avail. Although several reports of faulty vaporizers are present in literature (2–5), this type of fault has not been reported previously. We think that probably the anesthetic might have reacted with the chamber causing persistent damage to the chamber, resulting in leakage and loss of anesthetic. Although we do not know the exact cause/mechanism of this damage, anesthesiologists should be aware of this potential problem.Figure 2.: Multiple cracks in the filling chamber beneath the crystal screen observed after draining out halothane.Babita Ghai, MD, DNB Jeetinder Kaur Makkar, MD, DNB Department of Anaesthesia and Intensive Care Post Graduate Institute of Medical Education and Research Chandigarh, India [email protected]

Calibration of the Capintec CRC-712M dose calibrator for 18F

Primary standardisation was performed on a solution of 18F using the 4 πβ– γ coincidence counting efficiency-tracing extrapolation method with 60Co used as a tracer nuclide. The result was used to calibrate the ANSTO secondary standard ionisation chamber which is used to disseminate Australian activity standards for gamma emitters. Using the secondary activity standard for 18F, the Capintec CRC-712M dose calibrator at the Australian National Medical Cyclotron (NMC) Positron Emission Tomography (PET) Quality Control (QC) Section was calibrated. The dial setting number recommended by the manufacturer for the measurement of the activity of 18F is 439. In this work, the dial setting numbers for the activity measurement of the solution of 18F in Wheaton vials were experimentally determined to be 443±12, 446±12, 459±11, 473±15 for 0.1, 1, 4.5 and 9 ml solution volumes, respectively. The uncertainties given above are expanded uncertainties ( k = 2 ) giving an estimated level of confidence of 95%. The activities determined using the manufacturer recommended setting number 439 are 0.8%, 1.4%, 4.0% and 6.5% higher than the standardised activities, respectively. It is recommended that a single dial setting number of 459 determined for 4.5 ml is used for 0.1–9 ml solution in Wheaton vials in order to simplify the operation procedure. With this setting the expended uncertainty ( k = 2 ) in the activity readout from the Capintec dose calibrator would be less than 6.2%.

Massive Inhalation of Desflurane due to Vaporizer Dysfunction

Massive Inhalation of Desflurane due to Vaporizer Dysfunction

Molecular Cloning of a Sixth Member of the K+-dependent Na+/Ca2+ Exchanger Gene Family, NCKX6

Bioinformatic and molecular cloning tools were used to identify and isolate cDNA clones from mouse and human tissues that encode the sixth member of the K(+)-dependent Na+/Ca2+ exchanger family, NCKX6. The mouse NCKX6 protein is 585 amino acids long and shares about 62% sequence similarity with previously identified exchangers in the alpha-repeat regions but has little primary sequence similarity outside these regions. NCKX6 transcripts of 4 kb are abundantly expressed in all tissues examined and are thus more broadly distributed than previously described NC(K)X family members. Two alternatively spliced products of this novel gene were identified that encode proteins of different length. The short isoform differs from the full-length isoform at the C-terminal hydrophobic domain as a result of a shift in the reading frame caused by the deletion of two exons. Both NCKX6 isoforms were expressed in HEK-293 cells. Functional analysis by digital imaging of fura-2 loaded transfected HEK-293 cells demonstrated that the short isoform exhibited K(+)-dependent Na+/Ca2+ exchange activity whereas the full-length isoform did not. The latter was retained within the endoplasmic reticulum, whereas the short isoform was present at the plasma membrane in transfected cells. Immunofluorescence studies examining NCKX6 expression in native tissue using an NCKX6-specific antibody showed intense labeling of the cardiac sarcolemmal membrane. The discovery of NCKX6 therefore reveals a novel member of the Na+/Ca2+ exchanger superfamily whose ubiquitous expression in all tissues suggests an important role for K(+)-dependent Na+/Ca2+ exchange in maintaining cellular Ca2+ homeostasis in diverse tissues and cell types.